Andrew Breitbart dead at 43 of natural causes at UCLA hospital

The exact cause of death was unclear, said the sources, who spoke on the condition of anonymity because the case was ongoing.

It's also unclear if he was stricken at the hospital or another location. [Updated at 10:13 a.m.: Breitbart’s father-in-law, actor Orson Bean, told The Times he collapsed on the sidewalk near his home while taking a nighttime walk.]

"Andrew passed away unexpectedly from natural causes shortly after midnight this morning in Los Angeles," Breitbart.com said. "We have lost a husband, a father, a son, a brother, a dear friend, a patriot and a happy warrior. "

Breitbart, 43, a star of the tea party movement, was a Hollywood-hating, mainstream-media-loathing conservative, according to a Times profile. After spending 10 years as editor of the Drudge Report and helping to launch the Huffington Post, in 2005 he launched his news aggregation site Breitbart.com, which was designed to counter what Breitbart described as the "bully media cabal" that he says ignores stories at odds with prevailing liberal orthodoxy. His goal, he says often, is to "destroy the institutional left."

His big splash came in 2009, when he posted an undercover video in which a pair of conservative activists posing as a prostitute and her boyfriend asked employees of the community group ACORN for help with a brothel that would house underage Salvadorans. ACORN was embarrassed when some of its workers seemed too helpful; Congress responded by defunding the organization.

In 2010, Breitbart posted a 2 1/2-minute video of Shirley Sherrod, a black employee of the U.S. Department of Agriculture, in which she appeared to make racially charged comments. It left viewers with the inaccurate impression Sherrod had deliberately not helped a white man save his family farm in 1986 when she worked for a Georgia nonprofit organization.

The furor from the video caused Sherrod to be fired; when it was later revealed her comments had been taken out of context, Agriculture Secretary Tom Vilsack called Sherrod to apologize and ask whether she would return to the department.

Breitbart's conservative news websites broke the story about the sexually charged tweets by Rep. Anthony Weiner (D-N.Y.), a scandal that led to his resignation.

The Times' Robin Abcarian visited his office in West Los Angeles in 2010. "The command center of Andrew Breitbart's growing media empire is a suite of offices on Sawtelle Boulevard in West Los Angeles with the temporary feel of a campaign office. Only the computers seem firmly anchored."

According to that profile, Breitbart lived in Westwood with his wife, Susie, and their four young children. He was adopted by moderately conservative Jewish parents and attended two of L.A.'s most exclusive private schools — Carlthorp and Brentwood.

His father, Gerald, owned Fox and Hounds, a landmark Tudor-style Santa Monica restaurant that later became the punk rock club Madame Wong's West. His mother, Arlene, was an executive at Bank of America in Beverly Hills and downtown L.A.